The United Kingdom's withdrawal from the EU will consume a lot of attention and time for both British and EU diplomats, potentially leaving Brussels more inward-looking and toothless in the years to come.

BRUSSELS -- Much ink has been spilled about a handful of pivotal elections in EU member states this year, and their potential to transform the European Union and its relations with neighbors and allies alike.

The populist backlash that fueled the Brexit vote and Donald Trump's U.S. presidential victory in 2016 -- and the Greek debt crisis before them -- is likely to continue in Europe.

The Dutch go to the polls in March, when the nativist, anti-Islam Freedom Party headed by Geert Wilders could win the biggest share of the vote and strongly influence coalition building.

France selects a new president in April and May, and the right-wing populist National Front's Marine Le Pen appears all but certain to reach the second round.

In September, the populist, Euroskeptical Alternative for Germany will enter the Bundestag in an election that threatens to weaken or unseat Chancellor Angela Merkel, who has become the public face of the current EU in many people's eyes.

But there are a number of other events on the 2017 schedule -- seemingly symbolic or plainly decisive -- that are keeping diplomats, military minds, and Eurocrats awake at night and could alter Europe's course for years to come. The result could be a European Union, and possibly NATO, that look a whole lot more introverted and chaotic to most observers.

NATO At 29?

The biggest get-together in Brussels this year is likely to be the "Trump summit" in the spring. It is an official NATO leaders summit and is meant to welcome the new U.S. president to Europe and get him acquainted with the workings of the alliance. Similar meetings were organized for both Barack Obama and George W. Bush when they entered office, but expect other NATO leaders and diplomats to be a bit more nervous for this one.

Will Trump be committed to the defense of NATO's eastern flank? Does he care about Afghanistan? Is he really that close to Vladimir Putin? Those are the questions they have been asking themselves ever since his election, and it is here that Europeans will get the first taste of what he really wants.

The reason no firm date for the "Trump summit" has been set is that NATO officials are keen to inaugurate Brussels' new NATO headquarters by hosting the meeting there. Construction of the 1 billion-euro ($1.1 billion) building started in 2010 and should be ready in the next few months. Ironically, it might be inaugurated at a welcoming summit for a U.S. president (and billionaire developer) who has been bluntly transactional about U.S. obligations under the alliance.

Around the same time, Montenegro will most likely become the alliance's 29th member (although some NATO countries, including the United States, must still ratify the accession). No diplomat who spoke to RFE/RL cited any major obstacles at this stage, but there is nervousness in the air. Montenegrin authorities have accused Russians of trying to destabilize their country during elections in October. Could such a move have been a desperate, foreign-backed effort to derail NATO accession, and, if so, is there more to come? Whatever the answer to those questions, one thing seems clear: This enlargement will almost certainly be the last for either NATO or the EU in a long time.

Centrifugal Forces

By the end of March, Brexit negotiations should be set in motion -- initially for two years, but it might take longer. The United Kingdom's withdrawal from the EU will consume a lot of attention and time for both British and EU diplomats, potentially leaving Brussels more inward-looking and toothless in the years to come. What impact will ongoing Brexit talks have, for example, on the renewal or expiration of the EU's economic sanctions against Russia, set to run out by the end of July?

EU divisions will otherwise be on full display at two events early in 2017. By the end of February, the EU Commission wants answers from Poland concerning the rule of law in that country, particularly the functioning of its Constitutional Court. It is a battle that has been going on ever since the right-wing Law and Justice party came to power in Warsaw in late 2015. Expect Poland to ignore the EU Commission and the EU Commission to abstain from sanctioning Warsaw since it knows that countries like Hungary are covering Poland's back. It will be widely perceived as a victory for illiberal democracy in the newish EU member states and a final blow for EU enlargement enthusiasts who frequently touted Poland as a poster child for the successful reintegration of former Warsaw Pact countries into mainstream Western politics.

Poland might also play a key role when it comes to renewing EU Council President Donald Tusk's mandate for another 2 1/2 years. The decision is likely to be made at an EU summit in March. But Tusk's archrival in Polish domestic politics, Law and Justice's Jaroslaw Kaczynski, has already signaled that he won't support a second term for his compatriot. Tusk can be reelected by a qualified majority, but questions over his standing could weaken one of Brussels' biggest Putin critics at a crucial stage in EU-Russian relations.

And on the topic of Russia, it's hard to imagine a complete thaw between Brussels and Moscow anytime too soon. But it's easier to envisage a possible settlement between the European Commission and Gazprom this spring over how the Russian state-owned energy giant operates on the EU single market. In 2015, the European Commission accused Gazprom of overcharging customers in Eastern and Central Europe and unfairly blocking rivals. Moscow is keen to avoid a massive fine, and might let itself be persuaded to respect Brussels' interpretation of those particular EU rules.

Shaken, Not Stirred

Then, on March 25, EU leaders will gather in Rome to mark the 60th anniversary of the signing of the treaty to launch the European Economic Community -- an early forerunner of today's EU. The plan is for leaders to come up with a clear new vision for the future of the bloc. But the question is whether this meeting won't instead be fraught by bickering over refugee quotas and cures to solve the EU's economic ills.

In November, the remains of the bloc's eastern policy will be scrutinized when the Eastern Partnership summit kicks off in Brussels. "Eastern partners" Georgia and Moldova already have Association Agreements with the EU; Ukraine is poised to have its Association Agreement sealed if the Dutch parliament manages to ratify the document in votes taking place in January and February. Moldovans will be joined by Georgians and Ukrainians in the spring for visa-free access to the EU.

Another Eastern Partnership member, Armenia, should finish negotiations on a partnership deal that excludes a free-trade area in the first half of the year; at around the same time, negotiations with Azerbaijan might commence on a similar deal. Questions will meanwhile be asked about what more the EU can offer its "eastern partners" and what the point really is of the partnership.

But the biggest headline could well be that Belarusian President Alyaksandr Lukashenka might show up after years as persona non grata during previous Eastern Partnership summits. The decision in February to lift sanctions against him and 169 other Belarusian officials (and several defense-sector companies) was criticized by Lukashenka detractors, who cited continued jailings and other repression targeting political dissidents and other regime critics.